[Backport] Bot finds original commit in wrong repository

See these PRs:
https://github.com/openjdk/jdk11u-dev/pull/8
https://github.com/openjdk/jdk11u-dev/pull/9

The comments referring to the original commit ends up pointing to the AdoptOpenJDK/openjdk-jdk mirror over openjdk/jdk official repo. See:
https://github.com/openjdk/jdk11u-dev/pull/9#issuecomment-853233285 pointing to:
https://github.com/AdoptOpenJDK/openjdk-jdk/commit/3341d361316def749c155242e6bf7fcbcb968531

It should have pointed to:
https://github.com/openjdk/jdk/commit/3341d361316def749c155242e6bf7fcbcb968531